Composite electrodes and methods of making the same

ABSTRACT

A composite electrode comprising a charge-conducting material, a charge-providing material bound to the charge-conducting material, and a plurality of single-walled carbon nanotubes bound to a surface of the charge-providing material. High-capacity electroactive materials that assure high performance are a prerequisite for ubiquitous adoption of technologies that require high energy/power density lithium (Li)-ion batteries, such as smart Internet of Things (IoT) devices and electric vehicles (EVs). Improved electrode performance and lifetimes are desirable. The disclosed electrode can have a Coulombic efficiency of 99% or greater, and a stable capacity retention after 100 cycles or more. Methods of making a composite electrode are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.16/978,443 filed 4 Sep. 2020, which is a US National Stage Applicationclaiming priority to PCT/US2019/020927 filed 6 Mar. 2019, which claimsthe benefit under 35 USC § 119(e), of U.S. Provisional PatentApplication No. 62/639,339, filed 6 Mar. 2018, the entire contents andsubstance of each being incorporated herein by reference in its entiretyas if fully set forth below.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under Grant No.DE-SC0012673 awarded by the US Department of Energy. The government hascertain rights in the invention.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not Applicable

SEQUENCE LISTING

Not Applicable

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINTINVENTOR

Not Applicable

BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure

The present disclosure relates generally to electrodes and methods ofmaking the same. Particularly, embodiments of the present disclosurerelate to composite electrodes.

2. Background

High-capacity electroactive materials that assure high performance are aprerequisite for ubiquitous adoption of technologies that require highenergy/power density lithium (Li)-ion batteries, such as smart Internetof Things (IoT) devices and electric vehicles (EVs). While high-capacityanode materials including silicon, tin, metal oxides and theirderivatives have been identified; they undergo massive volume changesand resultant poor electrochemistry, which is arguably the majorimpediment delaying their practical implementation. Specifically, crackformation and pulverization during volume expansion contributesubstantially to breakage of electronic pathways in electrodes and inturn, degradation of battery performance.

Efforts have been made to suppress the electrical breakdown throughintroduction of electrically conducting functionalities (e.g., carboncoatings, carbon nanotubes (CNTs), or graphene) onto the active materialsurface. Despite improvements in performance, these approaches are notsolely capable of maintaining electrical connectivity betweencracked/pulverized active particles during repeated charge-dischargecycles because of weak van der Waals interactions between carbon and theactive material surface. Thus, it is imperative to link the carbonaceousconducting agent (i.e., carbon nanotubes) and high-capacity activeparticles with a binding component. However, polymeric binders includingmodified carboxymethyl cellulose (CMC) and poly(acrylic acid) (PAA),utilized in enhanced high-capacity Li-ion battery electrodes, areintrinsically electrical insulators and would be expected to eventuallyincrease electrode resistance.

What is needed, therefore, is a composite electrode which suppresses theelectrochemical breakdown of the electrode and reduces stressful volumechanges during use, while maintaining or improving performance andconductivity. Embodiments of the present disclosure address this need aswell as other needs that will become apparent upon reading thedescription below in conjunction with the drawings.

BRIEF SUMMARY OF THE DISCLOSURE

The present invention relates to porous molecular structures and methodsfor making the same. An exemplary embodiment of the present inventionprovides a composite electrode, comprising a charge-conducting material,a charge-providing material bound to the charge-conducting material, anda plurality of single-walled carbon nanotubes bound to a surface of thecharge-providing material.

In an exemplary embodiment, a composite electrode comprises acharge-providing material comprising magnetite and single-walled carbonnanotubes bound to a surface of the charge-providing material.

In any of the embodiments disclosed herein, the composite electrode canfurther comprise a charge-conducting material.

In any of the embodiments disclosed herein, the charge-providingmaterial can be bound to the charge-conducting material.

In any of the embodiments disclosed herein, the charge-providingmaterial can comprise a metallic oxide.

In any of the embodiments disclosed herein, the charge-providingmaterial can comprise magnetite.

In any of the embodiments disclosed herein, the composite electrode canfurther comprise a first polymer binding the single-walled carbonnanotubes to the charge-providing material.

In any of the embodiments disclosed herein, the composite electrode canfurther comprise a second polymer binding the charge-providing materialto the charge-conducting material.

In any of the embodiments disclosed herein, the first polymer cancomprise a polymer with carboxylic acid side chains.

In any of the embodiments disclosed herein, the first polymer can bebound to the single-walled carbon nanotube layer through pi bond-pi bondstacking.

In another exemplary embodiment, a composite electrode comprises acharge-providing material, single-walled carbon nanotubes bound to asurface of the charge-providing material, and a polymer binding thesingle-walled carbon nanotubes to the charge-providing material, whereinthe polymer is poly[3-(potassium-4-butanoate) thiophene] (PPBT).

In another exemplary embodiment, a composite electrode comprises acharge-providing material bound by a first polymer to acharge-conducting material and single-walled carbon nanotubes bound by asecond polymer to a surface of the charge-providing material, whereinthe charge-providing material comprises silicon nanoparticles, and wherethe first polymer is carboxymethyl cellulose (CMC).

In another exemplary embodiment, a composite electrode comprises acharge-providing material and single-walled carbon nanotubes bound to asurface of the charge-providing material, wherein the compositeelectrode presents a Coulombic efficiency of 99% or greater and whereinthe charge-providing material comprises magnetite, and/or thecharge-providing material is bound by a first polymer to acharge-conducting material, the single-walled carbon nanotubes are boundto the surface of the charge-providing material by a second polymer, thecharge-providing material comprises silicon nanoparticles, and the firstpolymer is carboxymethyl cellulose (CMC), and/or the charge-providingmaterial is bound by a first polymer to a charge-conducting material,the single-walled carbon nanotubes are bound to the surface of thecharge-providing material by a second polymer, the charge-providingmaterial comprises magnetite and silicon nanoparticles, and the firstpolymer is carboxymethyl cellulose (CMC).

In any of the embodiments disclosed herein, the electrode can present aCoulombic efficiency of from 99.5% to 99.95%.

In another exemplary embodiment, a composite electrode comprises acharge-providing material and single-walled carbon nanotubes bound to asurface of the charge-providing material, wherein the compositeelectrode presents a Specific Capacity of 500 mAh/g or greater, andwherein the charge-providing material comprises magnetite, and/or thecharge-providing material is bound by a first polymer to acharge-conducting material, the single-walled carbon nanotubes are boundto the surface of the charge-providing material by a second polymer, thecharge-providing material comprises silicon nanoparticles, and the firstpolymer is carboxymethyl cellulose (CMC), and/or the charge-providingmaterial is bound by a first polymer to a charge-conducting material,the single-walled carbon nanotubes are bound to the surface of thecharge-providing material by a second polymer, the charge-providingmaterial comprises magnetite and silicon nanoparticles, and the firstpolymer is carboxymethyl cellulose (CMC).

In another exemplary embodiment, a composite electrode comprises acharge-providing material and single-walled carbon nanotubes bound to asurface of the charge-providing material, wherein the compositeelectrode presents a stable capacity retention of 75% or greater after100 cycles, and wherein the charge-providing material comprisesmagnetite, and/or the charge-providing material is bound by a firstpolymer to a charge-conducting material, the single-walled carbonnanotubes are bound to the surface of the charge-providing material by asecond polymer, the charge-providing material comprises siliconnanoparticles, and the first polymer is carboxymethyl cellulose (CMC),and/or the charge-providing material is bound by a first polymer to acharge-conducting material, the single-walled carbon nanotubes are boundto the surface of the charge-providing material by a second polymer, thecharge-providing material comprises magnetite and silicon nanoparticles,and the first polymer is carboxymethyl cellulose (CMC).

In another exemplary embodiment, a composite electrode comprises acharge-providing material and single-walled carbon nanotubes bound to asurface of the charge-providing material, wherein the compositeelectrode initial Specific Capacity changes by 5% or less after 200cycles or more, and wherein the charge-providing material comprisesmagnetite, and/or the charge-providing material is bound by a firstpolymer to a charge-conducting material, the single-walled carbonnanotubes are bound to the surface of the charge-providing material by asecond polymer, the charge-providing material comprises siliconnanoparticles, and the first polymer is carboxymethyl cellulose (CMC),and/or the charge-providing material is bound by a first polymer to acharge-conducting material, the single-walled carbon nanotubes are boundto the surface of the charge-providing material by a second polymer, thecharge-providing material comprises magnetite and silicon nanoparticles,and the first polymer is carboxymethyl cellulose (CMC).

In another exemplary embodiment, a composite electrode comprises acharge-providing material and single-walled carbon nanotubes bound to asurface of the charge-providing material, wherein the compositeelectrode undergoes a volume change of 40% or less after 100 cycles, andwherein the charge-providing material comprises magnetite, and/or thecharge-providing material is bound by a first polymer to acharge-conducting material, the single-walled carbon nanotubes are boundto the surface of the charge-providing material by a second polymer, thecharge-providing material comprises silicon nanoparticles, and the firstpolymer is carboxymethyl cellulose (CMC), and/or the charge-providingmaterial is bound by a first polymer to a charge-conducting material,the single-walled carbon nanotubes are bound to the surface of thecharge-providing material by a second polymer, the charge-providingmaterial comprises magnetite and silicon nanoparticles, and the firstpolymer is carboxymethyl cellulose (CMC).

In another exemplary embodiment, a composite electrode comprises acharge-providing material and single-walled carbon nanotubes, whereinthe improvement to the composite electrode is selected from the groupconsisting of the charge-providing material comprises magnetite, thecharge-providing material is bound by a first polymer to acharge-conducting material, the single-walled carbon nanotubes are boundto a surface of the charge-providing material by a second polymer, thecharge-providing material comprises silicon nanoparticles, and the firstpolymer is carboxymethyl cellulose (CMC), the charge-providing materialis bound by a first polymer to a charge-conducting material, thesingle-walled carbon nanotubes are bound to a surface of thecharge-providing material by poly[3-(potassium-4-butanoate) thiophene](PPBT), and the charge-providing material comprises siliconnanoparticles, the composite electrode further comprises acharge-conducting material bound to the charge-providing material bycarboxymethyl cellulose (CMC), the composite electrode presents aCoulombic efficiency of 99% or greater, the composite electrode presentsa Specific Capacity of 500 mAh/g or greater, the composite electrodepresents a stable capacity retention of 75% or greater after 100 cycles,the composite electrode initial Specific Capacity changes by 5% or lessafter 200 cycles or more, the composite electrode undergoes a volumechange of 25% or less after 100 cycles, and a combination thereof.

In another exemplary embodiment, in a method of making a compositeelectrode comprises a charge-providing material, single-walled carbonnanotubes, and a property, wherein the improvement to the methodcomprises dispersing the single-walled carbon nanotubes and a firstpolymer in a first solvent, combining the dispersion and a mixturepowder comprising the charge-providing material, filtering thecombination, and coating the filtrate on a substrate, wherein theproperty of the made composite electrode is selected from the groupconsisting of presenting a Coulombic efficiency of 99% or greater,presenting a Specific Capacity of 500 mAh/g or greater, presenting astable capacity retention of 75% or greater after 100 cycles, presentingan initial Specific Capacity that changes by 5% or less after 200 cyclesor more, undergoing a volume change of 25% or less after 100 cycles, anda combination thereof.

In any of the embodiments disclosed herein, the method can furthercomprise washing, with a nonsolvent, the filtrate and drying thefiltrate.

In any of the embodiments disclosed herein, the dispersion can be asolution, the mixture powder can further comprise a charge-conductingmaterial and a second polymer, the combination can be a suspension, thefiltrate can be an electroactive material, and coating the electroactivematerial on the substrate can form the composite electrode.

In any of the embodiments disclosed herein, the method can furthercomprise pressing the electrode to a predetermined density.

In any of the embodiments disclosed herein, the method can furthercomprise coating the electroactive material and a binder material to thesubstrate.

In any of the embodiments disclosed herein, the first polymer cancomprise a polymer with carboxylic acid side chains and the secondpolymer can comprise polyethylene glycol (PEG).

In any of the embodiments disclosed herein, the first polymer can bepoly[3-(potassium-4-butanoate) thiophene] (PPBT).

In any of the embodiments disclosed herein, the binder material cancomprise carboxymethyl cellulose (CMC).

In any of the embodiments disclosed herein, the binder material cancomprise a third polymer selected from the group consisting of PPBT,carboxymethyl cellulose (CMC), and styrene butadiene.

In another exemplary embodiment, a composite electrode comprises acharge-providing material, single-walled carbon nanotubes bound to asurface of the charge-providing material, and a conjugated polymerpossessing polar functionality to effectively anchor the single-walledcarbon nanotubes to the surface of the charge-providing material,wherein the conjugated polymer comprises poly[3-(potassium-4-butanoate)thiophene] (PPBT), and wherein the charge-providing material comprises amaterial selected from the group consisting of monodispersed Fe₃O₄spheres, silicon nanoparticles, metallic oxide, magnetite, and acombination thereof.

In another exemplary embodiment, a method of making a compositeelectrode comprises dispersing single-walled carbon nanotubes and afirst polymer in a first solvent, combining the dispersion and a mixturepowder comprising a charge-providing material, filtering thecombination, and coating the filtrate on a substrate.

In any of the embodiments disclosed herein, the method can furthercomprise washing, with a nonsolvent, the filtrate.

In any of the embodiments disclosed herein, the method can furthercomprise drying the filtrate.

In any of the embodiments disclosed herein, the dispersion can be asolution.

In any of the embodiments disclosed herein, the mixture powder canfurther comprise a charge-conducting material and a second polymer.

In any of the embodiments disclosed herein, the combination can be asuspension.

In any of the embodiments disclosed herein, the filtrate can be anelectroactive material.

In any of the embodiments disclosed herein, the electroactive materialon the substrate can form the composite electrode.

In any of the embodiments disclosed herein, the combination can be asuspension with the mixture powder further comprising acharge-conducting material, a second polymer, and a second solvent.

In any of the embodiments disclosed herein, the composite electrode canhave a property selected from the group consisting of presenting aCoulombic efficiency of 99% or greater, presenting a Specific Capacityof 500 mAh/g or greater, presenting a stable capacity retention of 75%or greater after 100 cycles, presenting an initial Specific Capacitythat changes by 5% or less after 200 cycles or more, undergoing a volumechange of 25% or less after 100 cycles, and a combination thereof.

In any of the embodiments disclosed herein, the coating can comprisecoating the electroactive material and a binder material to thesubstrate.

In any of the embodiments disclosed herein, the method can furthercomprise pressing the electrode to a predetermined density.

In any of the embodiments disclosed herein, the first polymer cancomprise a polymer with carboxylic acid side chains, and the secondpolymer can comprise polyethylene glycol (PEG).

In any of the embodiments disclosed herein, the first polymer canpoly[3-(potassium-4-butanoate) thiophene] (PPBT).

In any of the embodiments disclosed herein, the method can furthercomprise separating, prior to the filtering, the mixture powder from thesecond solvent, washing the electroactive material, and drying theelectroactive material.

In any of the embodiments disclosed herein, the charge-providingmaterial can comprise one or more materials selected from the groupconsisting of metal oxides, metallic oxides, iron alloys, magnetite,lithium, lithium ions, silicon nanoparticles, metal dioxides, oxygen,metal hydroxides, monofluorides, phosphates, and a combination thereof.

In any of the embodiments disclosed herein, the charge-conductingmaterial can comprise one or more materials selected from the groupconsisting of graphite, silver, copper, gold, aluminum, calcium,tungsten, zinc, nickel, lithium, iron, platinum, tin, gallium, niobium,steel, carbon steel, lead, titanium, electrical steel, manganin,constantan, stainless steel, mercury, manganese, amorphous carbon,germanium, salt water, and a combination thereof.

In any of the embodiments disclosed herein, the charge-conductingmaterial can comprise one or more materials selected from the groupconsisting of a material providing a conductivity of 100 S/m or greater,a material providing a conductivity of 1 Ω-m or less, and a combinationthereof.

In any of the embodiments disclosed herein, the single-walled carbonnanotubes can be bound to a surface of the charge-providing material bythe first polymer, the charge-providing material can be bound to asurface of the charge-conducting material by the second polymer, and thefirst and second polymers each can comprise one or more polymersselected from the group consisting of biopolymers, inorganic polymers,organic polymers, conductive polymers, copolymers, fluoropolymers,polyterpenes, phenolic resins, polyanhydrides, polyketones, polyesters,polyimides, polyolefins, rubbers, silicones, silicone rubbers,superabsorbent polymers, synthetic rubbers, vinyl polymers, and acombination thereof.

In any of the embodiments disclosed herein, the binder material cancomprise carboxymethyl cellulose (CMC).

In any of the embodiments disclosed herein, the binder material cancomprise a third polymer selected from the group consisting of PPBT,carboxymethyl cellulose (CMC), and styrene butadiene.

In any of the embodiments disclosed herein, the method can furthercomprise pressing the composite electrode to a predetermined density,wherein the dispersing comprises ultrasonication, wherein the combiningcomprises ultrasonication, wherein the separating uses densityseparation, wherein the filtering comprises vacuum filtering, andwherein the washing is with at least one nonsolvent.

In any of the embodiments disclosed herein, the charge-conductingmaterial can comprise graphite.

In any of the embodiments disclosed herein, the charge-providingmaterial can comprise silicon nanoparticles.

In any of the embodiments disclosed herein, the charge-providingmaterial can comprise a metallic oxide.

In any of the embodiments disclosed herein, the metallic oxide can bemagnetite.

In any of the embodiments disclosed herein, the electrode can furthercomprise a first polymer binding the plurality of single-walled carbonnanotubes to the charge-providing material.

In any of the embodiments disclosed herein, the electrode can furthercomprise a second polymer binding the charge-conducting material to thecharge-providing material.

In any of the embodiments disclosed herein, the first polymer cancomprise a polymer with carboxylic acid side chains.

In any of the embodiments disclosed herein, the first polymer can bebound to the single-walled carbon nanotube layer through pi bond-pi bondstacking.

In any of the embodiments disclosed herein, the first polymer can bepoly[3-(potassium-4-butanoate) thiophene] (PPBT).

In any of the embodiments disclosed herein, the second polymer can becarboxymethyl cellulose (CMC).

In any of the embodiments disclosed herein, the electrode can present aCoulombic efficiency of 99% or greater.

In any of the embodiments disclosed herein, the electrode can present aCoulombic efficiency of from 99.5% to 99.95%.

In any of the embodiments disclosed herein, the electrode can present aSpecific Capacity of 500 mAh/g or greater.

In any of the embodiments disclosed herein, the electrode can present astable capacity retention of 75% or greater after 100 cycles.

In any of the embodiments disclosed herein, the electrode initialSpecific Capacity can change by 5% or less after 200 cycles or more.

In any of the embodiments disclosed herein, the electrode can undergo avolume change of 40% or less after 100 cycles.

In any of the embodiments disclosed herein, the electrode can undergo avolume change of 25% or less after 100 cycles.

Another embodiment of the present disclosure provides a method of makinga composite electrode, the method comprising dispersing a plurality ofsingle-walled carbon nanotubes and a first polymer in a first solvent tocreate a solution, providing a mixture powder, comprising acharge-providing material, a charge-conducting material, and a secondpolymer, combining the solution and the mixture powder to create asuspension, filtering the suspension to obtain an electroactivematerial, and coating the electroactive material on a substrate to forman electrode.

In any of the embodiments disclosed herein, the method can furthercomprise washing, with at least one nonsolvent, the electroactivematerial.

In any of the embodiments disclosed herein, the method can furthercomprise drying the electroactive material.

In any of the embodiments disclosed herein, the mixture powder can be ina solution with a second solvent.

In any of the embodiments disclosed herein, the method can furthercomprise separating, using a density separation, the mixture powder fromthe second solvent.

In any of the embodiments disclosed herein, the filtering can comprisevacuum filtering.

In any of the embodiments disclosed herein, the dispersing can compriseultrasonication.

In any of the embodiments disclosed herein, the combining can compriseultrasonication.

In any of the embodiments disclosed herein, the method can furthercomprise pressing the electrode to a predetermined density.

In any of the embodiments disclosed herein, the method can furthercomprise applying a binder material to the electrode.

In any of the embodiments disclosed herein, the second polymer cancomprise polyethylene glycol (PEG).

In any of the embodiments disclosed herein, the first polymer cancomprise a polymer with carboxylic acid side chains.

In any of the embodiments disclosed herein, the first polymer can bebound to the single-walled carbon nanotube layer through pi bond-pi bondstacking.

In any of the embodiments disclosed herein, the first polymer can bepoly[3-(potassium-4-butanoate) thiophene] (PPBT).

In any of the embodiments disclosed herein, the second polymer can becarboxymethyl cellulose (CMC).

In any of the embodiments disclosed herein, the electrode can present aCoulombic efficiency of 99% or greater.

In any of the embodiments disclosed herein, the electrode can present aCoulombic efficiency of from 99.5% to 99.95%.

In any of the embodiments disclosed herein, the electrode can present aSpecific Capacity of 500 mAh/g or greater.

In any of the embodiments disclosed herein, the electrode can present astable capacity retention of 75% or greater after 100 cycles.

In any of the embodiments disclosed herein, the electrode initialSpecific Capacity can change by 5% or less after 200 cycles or more.

In any of the embodiments disclosed herein, the electrode can undergo avolume change of 40% or less after 100 cycles.

In any of the embodiments disclosed herein, the electrode can undergo avolume change of 25% or less after 100 cycles.

These and other aspects of the present invention are described in theDetailed Description of the Invention below and the accompanyingfigures. Other aspects and features of embodiments of the presentinvention will become apparent to those of ordinary skill in the artupon reviewing the following description of specific, exemplaryembodiments of the present invention in concert with the figures. Whilefeatures of the present invention may be discussed relative to certainembodiments and figures, all embodiments of the present invention caninclude one or more of the features discussed herein. Further, while oneor more embodiments may be discussed as having certain advantageousfeatures, one or more of such features may also be used with the variousembodiments of the invention discussed herein. In similar fashion, whileexemplary embodiments may be discussed below as device, system, ormethod embodiments, it is to be understood that such exemplaryembodiments can be implemented in various devices, systems, and methodsof the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate multiple embodiments of thepresently disclosed subject matter and serve to explain the principlesof the presently disclosed subject matter. The drawings are not intendedto limit the scope of the presently disclosed subject matter in anymanner.

FIG. 1 shows a rendering of an exemplary embodiment of a compositeelectrode with a rendering of an electrode of the prior art;

FIG. 2 shows an exploded view rendering of an exemplary embodiment of acomposite electrode;

FIGS. 3A-3B show Scanning Electron Microscope (SEM) images of acomposite electrode;

FIG. 4 is a flowchart of an exemplary method for making a compositeelectrode;

FIG. 5 is a flowchart of an exemplary method for making a compositeelectrode;

FIG. 6 shows graphs depicting the % volume change and specific capacitychange of an exemplary embodiment of a composite electrode; and

FIG. 7 shows a graph depicting the specific capacity change andCoulombic efficiency of an exemplary embodiment of a compositeelectrode.

DETAILED DESCRIPTION

Although certain embodiments of the disclosure are explained in detail,it is to be understood that other embodiments are contemplated.Accordingly, it is not intended that the disclosure is limited in itsscope to the details of construction and arrangement of components setforth in the following description or illustrated in the drawings. Otherembodiments of the disclosure are capable of being practiced or carriedout in various ways. Also, in describing the embodiments, specificterminology will be resorted to for the sake of clarity. It is intendedthat each term contemplates its broadest meaning as understood by thoseskilled in the art and includes all technical equivalents which operatein a similar manner to accomplish a similar purpose.

Herein, the use of terms such as “having,” “has,” “including,” or“includes” are open-ended and are intended to have the same meaning asterms such as “comprising” or “comprises” and not preclude the presenceof other structure, material, or acts. Similarly, though the use ofterms such as “can” or “may” are intended to be open-ended and toreflect that structure, material, or acts are not necessary, the failureto use such terms is not intended to reflect that structure, material,or acts are essential. To the extent that structure, material, or actsare presently considered to be essential, they are identified as such.

By “comprising” or “containing” or “including” is meant that at leastthe named compound, element, particle, or method step is present in thecomposition or article or method, but does not exclude the presence ofother compounds, materials, particles, method steps, even if the othersuch compounds, material, particles, method steps have the same functionas what is named.

It is also to be understood that the mention of one or more method stepsdoes not preclude the presence of additional method steps or interveningmethod steps between those steps expressly identified.

The components described hereinafter as making up various elements ofthe disclosure are intended to be illustrative and not restrictive. Manysuitable components that would perform the same or similar functions asthe components described herein are intended to be embraced within thescope of the disclosure. Such other components not described herein caninclude, but are not limited to, for example, similar components thatare developed after development of the presently disclosed subjectmatter.

As described above, a problem with current high-capacity electrodes isthe electrical breakdown, such as cracking and pulverization, and largevolume changes reducing the electrochemical efficiency of the material.Efforts have been made to suppress the electrical breakdown throughintroduction of electrically conducting functionalities onto the activematerial surface. Despite improvements in performance, these approachesare not solely capable of maintaining electrical connectivity betweencracked/pulverized active particles during repeated charge-dischargecycles because of weak van der Waals interactions between carbon and theactive material surface. Thus, it is imperative to link the carbonaceousconducting agent (carbon nanotubes) and high-capacity active particleswith a binding component. However, polymeric binders including modifiedsodium carboxymethyl cellulose (CMC) and poly(acrylic acid) (PAA),utilized in enhanced high-capacity Li-ion battery electrodes, areintrinsically electrical insulators and would be expected to eventuallyincrease electrode resistance. Furthermore, since they have pooraffinity with the conducting agent surface, it would additionally benecessary to effectively disperse and debundle the carbon nanotubes.

When studying materials to solve these problems, attention is turned tospecial polymeric binders. Water-soluble, carboxylate substitutedpolythiophenes, such as poly[3-(potassium-4-butanoate) thiophene](PPBT), have the potential to serve as a polymeric binder, or aphysical/chemical linker to render electroactive particles and carbonadditives well-connected through specific molecular interactions,thereby yielding stable, high-performance battery electrodes. The PPBThas relatively high electronic conductivity of 10⁻⁵ S cm⁻¹ when comparedwith polyvinylidene fluoride (PVDF; 10⁻⁸ S cm⁻¹); and experienceselectrochemical doping where the conjugated polymer undergoes reductionwithin the operating voltage of anode applications, enabling more rapidelectron transport. In addition, PPBT, with its conjugated backbone andside chain carboxylic moieties, has been shown to contribute tosingle-walled carbon nanotube (SWNT) dispersion and the formation ofcarboxylate bonds through interactions with surface electroactiveparticle hydroxyl groups. In particular, the pi-conjugated polythiophenebackbone physically interacts with the graphene-like electron richnanotube surface, while the solubilizing carboxylate substituted sidechains support SWNT debundling and dispersion in water.

Disclosed herein is a composite electrode. In order to suppresselectrical breakdown, carbon nanotubes are utilized to contain theactive material and prevent large cracking, volume changes, orpulverization. In order to maintain conductive performance, bindingmaterial is needed to bind the carbon nanotubes to the active material.According to some embodiments, the used of a carboxylated polythiophenelinker to securely bind SWNT electrical networks onto the surface of anactive material as found to ensure the electrical and structuralstability of the electrode. Beneficially, this architecture effectivelycaptured cracked/pulverized particles that typically form as a result ofrepeated active material volume changes that occur during charging anddischarging. Thus, changes in electrode thickness were suppressedsubstantially, stable SEI layers were formed, electrode resistance wasreduced, and enhanced electrode kinetics was observed. Together, thesefactors led to excellent electrochemical performance.

Disclosed herein are composite electrodes. Embodiments of the presentdisclosure can provide a composite electrode comprising acharge-conducting material, a charge-providing material bound to thecharge-conducting material, and a plurality of SWNTs bound to a surfaceof the charge-providing material. In some embodiments, thecharge-conducting material can be any electrically active material. Inother words, the charge-conducting material can be a material with a lowresistance able to provide electron flow through the material. Suitableexamples or a charge-conducting material can include, but are notlimited to, graphite, silver, copper, gold, aluminum, calcium, tungsten,zinc, nickel, lithium, iron, platinum, tin, gallium, niobium, steel,carbon steel, lead, titanium, electrical steel, manganin, constantan,stainless steel, mercury, manganese, amorphous carbon, germanium, saltwater, a combination thereof, and the like.

In some embodiments, the charge-conducting material can be any materialproviding a conductivity of 100 S/m or greater (e.g., 200 S/m orgreater, 300 S/m or greater, 400 S/m or greater, 500 S/m or greater,1000 S/m or greater, 5000 S/m or greater, or 10000 S/m or greater). Insome embodiments, the charge-conducting material can be any materialproviding a conductivity of 1 Ω-m or less (e.g., 0.1 Ω-m or less, 0.01Ω-m or less, 0.001 Ω-m or less, or 0.0001 Ω-m or less).

In some embodiments, the disclosed composite electrode can comprise acharge-providing material. In some embodiments, the charge-providingmaterial can be any material configured to provide a flow of electronswhile undergoing a redox reaction while in use. Suitable examples ofcharge-providing materials can include, but are not limited to, metaloxides, metallic oxides, iron alloys, magnetite, lithium, lithium ions,silicon nanoparticles, metal dioxides, oxygen, metal hydroxides,monofluorides, phosphates, and the like. In other words, acharge-providing material is an active material that facilitates theelectrochemical reaction by acting as an electron source or an electronsink. As used herein, the term “active material” refers to a materialthat facilitates the electrochemical reaction by acting as an electronsource or an electron sink.

In some embodiments, the disclosed composite electrode can comprise aplurality of single-walled carbon nanotubes (SWNTs) bound to a surfaceof the charge-providing material. In some embodiments, the SWNTs can bein any configuration, such as armchair, chiral, zigzag, or a combinationthereof.

In some embodiments, the disclosed composite electrode can comprise oneor more polymers. In some embodiments, the electrode can comprise afirst polymer binding the SWNTs to the charge-providing material. Insome embodiments, the electrode can comprise a second polymer bindingthe charge-conducting material to the charge-providing material. In anyof the embodiments disclosed herein, the first and second polymer can beany polymer. Suitable examples of a polymer can include, but are notlimited to, biopolymers, inorganic polymers, organic polymers,conductive polymers, copolymers, fluoropolymers, polyterpenes, phenolicresins, polyanhydrides, polyketones, polyesters, polyimides (such asMatrimid 5218 or 6FDA-DAM), polyolefins, rubbers, silicones, siliconerubbers, superabsorbent polymers, synthetic rubbers, vinyl polymers, ora combination thereof.

Other suitable examples of the polymer can include, but are not limitedto, polyester resin, polyurethanes, polyurea, vulcanized rubber,bakelite, duroplast, urea formaldehyde, melamine resin, diallylphthalate, epoxy resin, benzoxazines, polyimides, bismaleimides, cyanateesters, furan resins, silicone resins, thiolyte, vinyl ester, acrylic,polymethyl methacrylate, acrylonitrile butadiene styrene, chlorinatedpolyvinyl chloride, nylon, polylactic acid, polybenzimidazole,polycarbonate, polyether sulfone, polyoxymethylene, polyether etherketone, polyethylene, polyphenylene sulfide, polypropylene, polystyrene,polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene,polyisoprene, polybutadiene, chloroprene, butyl rubber, halogenatedbutyl rubber, styrene butadiene, nitrile rubber, halogenated nitrilerubber, ethylene propylene rubber, ethylene propylene diene rubber,epichlorohydrin rubber, polyacrylic rubber, silicone rubber,fluorosilicone, fluoroelastomers, perfluoroelastomers, polyether blockamides, chlorosulfonated polyethylene, ethylene vinyl acetate,thermoplastic elastomers, polysulfide rubber, cellulose acetate (CA),polymer of intrinsic micro porosity 1 (PIM-1),poly[3-(potassium-4-butanoate) thiophene] (PPBT), carboxymethylcellulose (CMC), polyethylene glycol (PEG), or a combination thereof.

Additional examples of suitable polymers useable include substituted orunsubstituted polymers and may be selected from polysulfones;poly(styrenes), including styrene-containing copolymers such asacrylonitrilestyrene copolymers, styrene-butadiene copolymers andstyrene-vinylbenzylhalide copolymers; polycarbonates; cellulosicpolymers, such as cellulose acetate-butyrate, cellulose propionate,ethyl cellulose, methyl cellulose, nitrocellulose, etc.; polyamides andpolyimides, including aryl polyamides and aryl polyimides; polyethers;polyetherimides; polyetherketones; polyethersulfones; poly(aryleneoxides) such as poly(phenylene oxide) and poly(xylene oxide);poly(esteramide-diisocyanate); polyurethanes; polyesters (includingpolyarylates), such as polyethylene terephthalate, poly(alkylmethacrylates), poly(acrylates), poly(phenylene terephthalate), etc.;polypyrrolones; polysulfides; polymers from monomers havingalpha-olefinic unsaturation other than mentioned above such as poly(ethylene), poly(propylene), poly(butene-1), poly(4-methyl pentene-1),polyvinyls, e.g., poly(vinyl chloride), poly(vinyl fluoride),poly(vinylidene chloride), poly(vinylidene fluoride), poly(vinylalcohol), poly(vinyl esters) such as poly(vinyl acetate) and poly(vinylpropionate), poly(vinyl pyridines), poly(vinyl pyrrolidones), poly(vinylethers), poly(vinyl ketones), poly(vinyl aldehydes) such as poly(vinylformal) and poly(vinyl butyral), poly(vinyl amides), poly(vinyl amines),poly(vinyl urethanes), poly(vinyl ureas), poly(vinyl phosphates), andpoly(vinyl sulfates); polyallyls; poly(benzobenzimidazole);polyhydrazides; polyoxadiazoles; polytriazoles; poly (benzimidazole);polycarbodiimides; polyphosphazines; etc., and interpolymers and thelike.

In some embodiments, the polymer can be selected from carboxylatesubstituted polythiophenes. For example, the first polymer binding theSWNTs to a surface of the charge-providing material can bepoly[3-(potassium-4-butanoate) thiophene] (PPBT). PPBT has relativelyhigh electronic conductivity of approximately 10⁻⁵ S cm⁻¹ when comparedwith other polymers, and experiences electrochemical doping where theconjugated polymer undergoes reduction within the operating voltage ofanode applications, enabling more rapid electron transport. In addition,PPBT, with its conjugated backbone and side chain carboxylic moieties,has been shown to contribute to SWNT dispersion and the formation ofcarboxylate bonds through interactions with surface electroactiveparticle —OH groups.

In particular, the π-conjugated polythiophene backbone physicallyinteracts with the graphene-like electron rich nanotube surface, whilethe solubilizing carboxylate substituted side chains support SWNTdebundling and dispersion in water. In an exemplary embodiment, PPBT canbe used to bind the SWNTs to the charge-providing material (such asmagnetite) as the first polymer, and CMC and/or PEG can be used to bindthe charge-providing material (such as magnetite) to thecharge-conducting material (such as graphite) as the second polymer. Aswould be appreciated by one of ordinary skill in the art, such anembodiment would provide secure binding between the SWNT surface and theactive material, and secure binding within the active material betweenthe charge-providing material and the charge-conducting material.

According to some embodiments, the components of the presently disclosedcomposite electrode can be present in any amount to confer a desirableproperty to the electrode. In some embodiments, the electrode canpresent a Coulombic efficiency of 99% or greater (e.g., 99.05% orgreater, 99.1% or greater, 99.15% or greater, 99.2% or greater, 99.25%or greater, 99.3% or greater, 99.35% or greater, 99.4% or greater,99.45% or greater, 99.5% or greater, 99.55% or greater, 99.6% orgreater, 99.65% or greater, 99.7% or greater, 99.75% or greater, 99.8%or greater, 99.85% or greater, 99.9% or greater, or 99.95% or greater).In some embodiments, the electrode can present a specific capacity of500 mAh/g or greater (e.g., 600 mAh/g or greater, 700 mAh/g or greater,800 mAh/g or greater, 900 mAh/g or greater, 1000 mAh/g or greater, 2000mAh/g or greater, 3000 mAh/g or greater, or 4000 mAh/g or greater). Aswould be appreciated by one of ordinary skill in the art, such anembodiment would provide for high capacity electrodes viable forlarge-scale industrial use, rivaling the performance of currently usedelectrodes.

As used herein, the term “cycle” or “cycles” shall refer to the periodof time for an electrochemical cell to exhaust its potential andrecharge to a maximum rechargeable potential. In some embodiments, theelectrode can present a stable capacity retention of 75% or greater(e.g., 80% or greater, 85% or greater, 90% or greater, or 95% orgreater) after 100 cycles. In some embodiments, the electrode canpresent a specific capacity change of 5% or less (e.g., 4% or less, 3%or less, 2% or less, or 1% or less) after 200 cycles. In someembodiments, the electrode can undergo a volume change of 40% or less(e.g., 35% or less, 30% or less, 25% or less, 20% or less, 15% or less,10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less,4% or less, 3% or less, 2% or less, or 1% or less) after 100 cycles. Aswould be appreciated by one or ordinary skill in the art, such anembodiment would provide an electrode with reduced tendency to crack,leading to longer use lifetimes.

Embodiments of the present disclosure can provide a solvent. The solventcompound can be any substance able to substantially dissolve any desiredcomponents to create a liquid solution at room temperature and pressure.In some embodiments, the components as disclosed herein can create auniformly dispersed slurry when added to the solvent. Suitable examplesof a solvent can include, but are not limited to, nonpolar solvents,polar aprotic solvents, polar protic solvents, water-miscible solvents,or a combination thereof.

There are many examples of appropriate solvents known to one of ordinaryskill in the art, but suitable examples can include, but are not limitedto, acetaldehyde, acetic acid, acetone, acetonitrile, butanediol,butoxyethanol, butyric acid, diethanolamine, diethylenetriamine,dimethyl acetamide (DMAc), dimethylformamide (DMF), dimethoxy ethane,dimethyl sulfoxide (DMSO), dioxane, ethanol, ethylamine, ethyleneglycol, formic acid, furfuryl alcohol, glycerol, methanol, methyldiethanolamine, methyl isocyanide, N-methyl-2-pyrrolidone (NMP),propanol, propanediol, propanoic acid, propylene glycol, pyridine,tetrahydrofuran (THF), triethylene glycol, ethylene glycol, water,dimethyl hydrazine, hydrazine, hydrofluoric acid, hydrogen peroxide,nitric acid, sulfuric acid, pentane, cyclopentane, hexane, cyclohexane,benzene, toluene, chloroform, diethyl ether, dichloromethane, or acombination thereof.

Reference will now be made in detail to exemplary embodiments of thedisclosed technology, examples of which are illustrated in theaccompanying drawings and disclosed herein. Wherever convenient, thesame references numbers will be used throughout the drawings to refer tothe same or like parts.

FIGS. 4-5 illustrate exemplary embodiments of the presently disclosedmethod of making a composite electrode.

In FIG. 4 , a method for making a composite electrode is disclosedherein. In block 410, a plurality of single-walled carbon nanotubes(SWNTs) and a first polymer, such as PPBT, can be dispersed in a firstsolvent to create a solution. In some embodiments, the solution can bemixed using ultrasonication. Other methods of mixing are contemplated,such as agitation, magnetic stir bars, rollers, and the like. It isunderstood that, in some embodiments, the solution can comprise otherspecies, such as inhibitors, catalysts, nonsolvents, and the like.

In block 420, a mixture can be provided comprising a charge-providingmaterial, a charge-conducting material, and a second polymer. In someembodiments, the mixture can comprise other species, such as inhibitors,catalysts, nonsolvents, and the like. In some embodiments, the mixturecan be in a solution with a second solvent. In some embodiments, themixture can be removed from the second solvent by way of a densityseparation. Suitable examples of a density separation can includecentrifugation, float tanks, cyclones, and the like.

In block 430, the solution and the mixture can be combined to create asuspension. In some embodiments, the suspension can be mixed usingultrasonication. Other methods of mixing are contemplated, such asagitation, magnetic stir bars, rollers, and the like. It is understoodthat, in some embodiments, the suspension can comprise other species,such as inhibitors, catalysts, nonsolvents, and the like.

In block 440, the suspension can be filtered to obtain a solidelectroactive material. In some embodiments, the filtering can comprisevacuum filtering. Suitable examples of a filter can include a screen, amesh, a sieve, and the like. Other methods of filtration are considered,such as reverse osmosis, bag filters, paper filters, and the like.

In block 450, the solid electroactive material can be coated onto asubstrate to form an electrode. In some embodiments, the substrate canbe any solid material able to support the electroactive material.Suitable examples of a substrate can include, but are not limited to,copper mesh, copper foil, aluminum foil, and the like.

In FIG. 5 , a method for making a composite electrode is disclosedherein. Blocks 510 to 550 remain substantially analogous to theexemplary disclosure of FIG. 4 , with all the considerations andembodiments therein.

In block 560, the electroactive material coated on the substrate can bewashed with a nonsolvent. The nonsolvent can be any materialsubstantially unable to dissolve the electroactive material, such aswater, ethanol, or acetone. Additionally, the washing of theelectroactive material can be performed prior to the coating of thesubstrate with the electroactive material.

In block 570, the electrode can be dried. In some examples, theelectrode can be dried in a fume hood, oven, convection oven, vacuumoven, or the like.

In block 580, the electrode can be pressed to present a predetermineddensity. Suitable examples of pressing can include, but are not limitedto, hydraulic press, gravity press, weighted press, compression molding,and the like.

Reference will now be made in detail to exemplary embodiments of thedisclosed technology, examples of which are illustrated in theaccompanying drawings and disclosed herein. Wherever convenient, thesame references numbers will be used throughout the drawings to refer tothe same or like parts.

EXAMPLES

The following examples are provided by way of illustration but not byway of limitation.

Example 1 Materials and Methods

Monodispersed spherical Fe₃O₄ particles (˜500 nm in diameter) weresynthesized by a solvothermal method reported by Fan et al. Theprecursor solution was prepared by FeCl₃·6H₂O (2.16 g) and CH₃COONa·3H₂O(5.76 g) dissolved in 40 mL of ethylene glycol (EG) to form homogeneoussolution with stirring for 24 hours, and then sealed in a Teflon linedstainless autoclave (45 mL capacity), in which the concentration ofFeCl₃·6H₂O was 0.200 mol L⁻¹. The autoclave was heated to 200° C. for 8hours, and then cooled to room temperature. After sequentially washingseveral times with deionized water and ethanol using a centrifuge,monodispersed Fe₃O₄ spheres (sFe₃O₄) were produced. As synthesizedsFe₃O₄ particles, composed of small Fe₃O₄ crystallites (˜71 nm), have anaverage size of 498 nm.

For the preparation of sFe₃O₄ particles coated with PEG (PEG-sFe₃O₄), 1g of sFe₃O₄ powders in 10 g ethanol adding 8 mL of PEG 1500 solution(50% w/v, Sigma-Aldrich) were sonicated for 30 minutes in the ice bathwith an ultrasonic probe. The PEG-sFe₃O₄ powders were washed andextracted by centrifuge separation using acetone with speed of 6000 rpmfor 10 minutes three times. PPBT (M_(w): 16 kDa, polydispersity: 2.2,the head to tail regioregularity: 89%) was purchased from Rieke MetalsInc. For the preparation of SWNT-sFe₃O₄, the mixture of SWNT (10 mg,Sigma-Aldrich) in PPBT solution (20 mg of PPBT, 4 mL of deionized water)was sonicated for 15 minutes in the ice bath with an ultrasonic probe.

After adding PEG-sFe₃O₄ (100 mg) into the SWNT dispersion, the mixturesuspension was subjected to further ultrasonication for 3 minutes. Theresultant SWNT/PEG-sFe₃O₄ suspension was vacuum-filtrated onto amembrane filter (PVDF membrane filter with pore size of 0.22 μm, EMDmillipore) adding sufficient water, ethanol and acetone for washing.As-filtrated powders was finally vacuum-dried at 110° C. for overnight,eventually producing SWNT-sFe₃O₄ electroactive particles. TheSWNT-sFe₃O₄ particles assisted by SDBS surfactant (no PPBT linkagesample) were prepared by the same process mentioned above, except forthe SWNT suspension preparation using SDBS surfactant solution(concentration=1.0 wt % in water) instead of PPBT solution.

In case of Si NPs (50-70 nm, US Research Nanomaterials, Inc.), materialpreparation for SWNT anchoring with PPBT links followed the sameprocedure with SWNT-sFe₃O₄ preparation. Terephthalic acid (≥98% purity)and 2-aminoterephthalic acid (≥99+% purity) were purchased from SigmaAldrich and used with no further purification to create MIL-53(Al) andMIL-53-NH₂(Al) samples, respectively. Trimesic acid (95% purity) fromSigma Aldrich was used without further purification.

Working electrodes were made by blade-coating electrode slurry on the Cufoil substrate with active material (sFe₃O₄, SWNT-sFe₃O₄, Si NPs,SWNT-Si NPs), carbon black (CB) and binder (PPBT, sodium carboxymethylcellulose (CMC)). The electrode comprising SWNT-sFe₃O₄ (or sFe₃O₄), CB,and binder (CMC or PPBT) was 71.4:14.3:14.3 in a mass ratio, whereas52:34:14 for the electrode comprising active material (Si NPs, SWNT-SiNPs), CB, and binder (CMC or PPBT). Deionized water was used as asolvent. The sFe₃O₄ and Si NPs mass loading in the present study wastypically ˜1.9-3.0 mg cm⁻² and ˜0.8-1.9 mg cm², respectively. Theseprepared electrodes were pre-evaporated at 65° C. for 3 hours andcompletely evaporated at 110° C. for 12 hours in a vacuum oven, and thenpressed until the density of the electrode became ˜0.7-0.9 g cm⁻³.

2032-type coin cells (MTI corp.) were used for electrochemicalmeasurements. Lithium metal was used as a counter electrode and 1.2 MLiPF₆ in ethylene carbonate (EC) and diethyl carbonate (DEC) (1:1 byvolume) with 10 wt % fluoroethylene carbonate (FEC) for long cyclestability, was utilized as an electrolyte. When testing coin cellscomprising sF₃O₄-based electrodes, only constant current (CC) conditionwas used (i.e., lithiated to 0.01 V and delithiated to 3.0 V at the setvalue of current density), whereas when measuring coin cells comprisingSi NPs-based electrodes, a constant current (CC)-constant voltage (CV)technique was applied: the coin cell was lithiated to 0.01 V at the setvalue of current density under constant current (CC) condition and thenmaintained at constant voltage (CV) of 0.01 V until the current densitybecame 0.05 C. In turn, the cell was delithiated to 1.5 V at the setvalue of current density under CC condition. Before electrochemicaltesting, all the coin cells were charging and discharging with thecurrent density of 0.1 C to confirm their capacity and initialefficiency. The tests were then proceeded for cycling performance andrate capability.

Example 2 Materials and Methods

Prior to the integration with SWNTs using a PPBT component, PEG coatingon the c-SiO_(x) (KSC1064, Shin-Etsu Chemical Co., Ltd.) surface wasrequired. For the preparation of c-SiO_(x) particles coated with PEG(PEG-c-SiO_(x)), 1 g of c-SiO_(x) powders in 10 g ethanol and 8 mL ofPEG 1500 solution (50% w/v, Sigma-Aldrich) were sonicated for 15 minutesin the ice bath with an ultrasonic probe. The PEG-c-SiO_(x) powders werewashed and extracted by centrifuge separation using acetone with speedof 6000 rpm for 10 minutes three times. For the preparation ofSWNT-c-SiO_(x), the mixture of SWNT (10 mg, Sigma-Aldrich) in PPBTsolution (20 mg of PPBT, 4 mL of deionized water) was sonicated for 15minutes in the ice bath with an ultrasonic probe. PPBT (M_(w): 16 kDa,polydispersity: 2.2, the head to tail regioregularity: 89%) waspurchased from Rieke Metals Inc.

After adding as-prepared PEG-c-SiO_(x) (100 mg) into the SWNT-dispersedPPBT solution, the mixture suspension was subjected to furtherultrasonication for 3 minutes. The resultant SWNT/PEG-c-SiO_(x)suspension was vacuum-filtrated onto a membrane filter (PVDF membranefilter with pore size of 0.22 μm, EMD Millipore) adding sufficientwater, ethanol and acetone for washing. As-filtrated powders was finallyvacuum-dried at 110° C. for overnight, finally preparing SWNT-c-SiO_(x)electroactive particles. The SWNT-c-SiO_(x) particles assisted by SDBSsurfactant (no PPBT linkage sample) were prepared by the same processmentioned above, except for the SWNT suspension preparation using SDBSsurfactant solution (concentration=1.0 wt % in water) instead of PPBTsolution.

Working electrodes were made by blade-coating electrode slurry on the Cufoil substrate with active material (c-SiO_(x), SWNT-c-SiO_(x),c-SiO_(x)/graphite blend, SWNT-c-SiO_(x)/graphite blend), carbon black(CB) and binder (PPBT, sodium carboxymethyl cellulose (CMC), CMC/styrenebutadiene rubber (SBR)). The electrode comprising SWNT-c-SiO_(x) (orc-SiO_(x)), CB, and binder (CMC or PPBT) was 52:34:14 in a mass ratio.Similarly, in the graphite-blended systems with PPBT or CMC binder, themass ratio of SWNT-c-SiO_(x)/graphite blend, CB, and binder was52:34:14. When fabricating CMC/SBR binder-based electrodes, activematerial (c-SiO_(x)/graphite blend, or SWNT-c-SiO_(x)/graphite blend),CB, CMC, and SBR were 95.8:1.7:1.5:1 in a mass ratio.

In the graphite-blended system, the active material was prepared byblending SWNT-c-SiO_(x) with graphite in a mass ratio of 30:70. Theseprepared electrodes were pre-evaporated at 65° C. for 3 hours andcompletely evaporated at 110° C. for 12 hours in a vacuum oven, and thenpressed until the density of the electrode became ˜0.7-0.9 g cm⁻³.

2032-type coin cells (MTI corp.) were used for electrochemicalmeasurements. Lithium metal was used as a counter electrode and 1.2 MLiPF₆ in ethylene carbonate (EC) and diethyl carbonate (DEC) (1:1 byvolume) with 10 wt % fluoroethylene carbonate (FEC) for long cyclestability, was utilized as an electrolyte. When testing coin cells, aconstant current (CC)-constant voltage (CV) technique was applied: thecoin cell was lithiated to 0.01 V at the set value of current densityunder CC condition and then maintained at CV of 0.01 V until the currentdensity became 0.05 C. In turn, the cell was delithiated to 1.5 V at theset value of current density under CC condition. Before electrochemicaltesting, all the coin cells were charging and discharging with thecurrent density of 0.1 C to confirm their capacity and initialefficiency. The tests were then proceeded for cycling performance andrate capability.

Example 3 Methods

A prototype full cell sealed with an aluminumized polymer pouch wasfabricated with a negative/positive (nip) ratio of ˜1.08; the anode andcathode areal capacities were 3.15 mAh cm⁻² and 2.93 mAh cm⁻². Thecathode was prepared by blade-coating electrode slurry on an aluminum(Al) foil substrate with a commercialized lithium cobalt oxide (LiCoO₂,or LCO), CB, and polyvinylidene fluoride (PVDF) binder in a mass ratioof 94:3:3 using N-methyl-2-pyrrolidone (NMP) as the solvent and dried at110° C. for 1 hour, and then pressed until the density of the electrodebecame ˜3.8 g cm⁻³. The Al pouch-type full cells, composed of a porouspolyethylene (PE) separator sandwiched between anode and cathode, wereassembled. The electrolyte comprising 1.2 M LiPF₆ in EC/DEC (1:1 byvolume) with 10 wt % FEC was injected and the pouch was completelysealed. The pouch-type cells were fabricated in a globe box filled withargon gas. The prepared full cells were precycled in the first threecycles over the potential range of 2.5-4.25 V at 0.05 C under CC/CV modefor charging to 4.25 V and maintained 4.25 V until the current densitybecame 0.03 C, and then CC mode for discharging to 2.5 V. The tests werethen proceeded for cycling performance and rate capability.

Example 4 Characterization Methods

The field-emission scanning electron microscopy (FE-SEM) images wereobserved on the surface view of the electrodes using Zeiss Ultra-60FE-SEM (or Hitachi SU-8230 FE-SEM) with an accelerating voltage of 5-10kV using the high vacuum mode at room temperature.

While the present disclosure has been described in connection with aplurality of exemplary aspects, as illustrated in the various figuresand discussed above, it is understood that other similar aspects can beused or modifications and additions can be made to the described aspectsfor performing the same function of the present disclosure withoutdeviating therefrom. For example, in various aspects of the disclosure,methods and compositions were described according to aspects of thepresently disclosed subject matter. However, other equivalent methods orcomposition to these described aspects are also contemplated by theteachings herein. Therefore, the present disclosure should not belimited to any single aspect, but rather construed in breadth and scopein accordance with the appended claims.

It is to be understood that the embodiments and claims disclosed hereinare not limited in their application to the details of construction andarrangement of the components set forth in the description andillustrated in the drawings. Rather, the description and the drawingsprovide examples of the embodiments envisioned. The embodiments andclaims disclosed herein are further capable of other embodiments and ofbeing practiced and carried out in various ways. Also, it is to beunderstood that the phraseology and terminology employed herein are forthe purposes of description and should not be regarded as limiting theclaims.

Accordingly, those skilled in the art will appreciate that theconception upon which the application and claims are based may bereadily utilized as a basis for the design of other structures, methods,and systems for carrying out the several purposes of the embodiments andclaims presented in this application. It is important, therefore, thatthe claims be regarded as including such equivalent constructions.

Furthermore, the purpose of the foregoing Abstract is to enable theUnited States Patent and Trademark Office and the public generally, andespecially including the practitioners in the art who are not familiarwith patent and legal terms or phraseology, to determine quickly from acursory inspection the nature and essence of the technical disclosure ofthe application. The Abstract is neither intended to define the claimsof the application, nor is it intended to be limiting to the scope ofthe claims in any way. Instead, it is intended that the invention isdefined by the claims appended hereto.

What is claimed is:
 1. A method of making a composite electrodecomprising: dispersing single-walled carbon nanotubes and a firstpolymer in a first solvent; combining the dispersion and a mixturepowder comprising a charge-providing material; filtering thecombination; and coating the filtrate on a substrate.
 2. The method ofclaim 1 further comprising: washing, with a nonsolvent, the filtrate;and drying the filtrate.
 3. The method of claim 1, wherein: thedispersion is a solution; the mixture powder further comprises: acharge-conducting material; and a second polymer; the combination is asuspension; the filtrate is an electroactive material; and coating theelectroactive material on the substrate forms the composite electrode.4. The method of claim 1, wherein the dispersion is a solution; whereinthe combination is a suspension with the mixture powder furthercomprising a charge-conducting material, a second polymer, and a secondsolvent; wherein the filtrate is an electroactive material; and whereincoating the electroactive material on the substrate forms the compositeelectrode.
 5. The method of claim 1, wherein mixture powder furthercomprises a charge-conducting material and a second polymer; and whereincomposite electrode has a property selected from the group consistingof: presenting a Coulombic efficiency of 99% or greater; presenting aSpecific Capacity of 500 mAh/g or greater; presenting a stable capacityretention of 75% or greater after 100 cycles; presenting an initialSpecific Capacity that changes by 5% or less after 200 cycles or more;undergoing a volume change of 25% or less after 100 cycles; and acombination thereof.
 6. The method of claim 3, wherein coating comprisescoating the electroactive material and a binder material to thesubstrate.
 7. The method of claim 3 further comprising pressing theelectrode to a predetermined density.
 8. The method of claim 3, whereinthe first polymer comprises a polymer with carboxylic acid side chains;and wherein the second polymer comprises polyethylene glycol (PEG). 9.The method of claim 3, wherein the first polymer ispoly[3-(potassium-4-butanoate) thiophene] (PPBT).
 10. The method ofclaim 3, wherein the electrode presents a Coulombic efficiency of 99% orgreater.
 11. The method of claim 3, wherein the electrode presents aSpecific Capacity of 500 mAh/g or greater.
 12. The method of claim 3,wherein the electrode presents a stable capacity retention of 75% orgreater after 100 cycles.
 13. The method of claim 3, wherein theelectrode initial Specific Capacity changes by 5% or less after 20cycles or more.
 14. The method of claim 3, wherein the electrodeundergoes a volume change of 40% or less after 100 cycles.
 15. Themethod of claim 4 further comprising: separating, prior to thefiltering, the mixture powder from the second solvent; washing theelectroactive material; and drying the electroactive material.
 16. Themethod of claim 5, wherein the charge-providing material comprises oneor more materials selected from the group consisting of metal oxides,metallic oxides, iron alloys, magnetite, lithium, lithium ions, siliconnanoparticles, metal dioxides, oxygen, metal hydroxides, monofluorides,phosphates, and a combination thereof; and wherein the charge-conductingmaterial comprises one or more materials selected from the groupconsisting of graphite, silver, copper, gold, aluminum, calcium,tungsten, zinc, nickel, lithium, iron, platinum, tin, gallium, niobium,steel, carbon steel, lead, titanium, electrical steel, manganin,constantan, stainless steel, mercury, manganese, amorphous carbon,germanium, salt water, and a combination thereof.
 17. The method ofclaim 5, wherein the charge-conducting material comprises one or morematerials selected from the group consisting of a material providing aconductivity of 100 S/m or greater, a material providing a conductivityof 1 Ω-m or less, and a combination thereof.
 18. The method of claim 5,wherein the single-walled carbon nanotubes are bound to a surface of thecharge-providing material by the first polymer; wherein thecharge-providing material is bound to a surface of the charge-conductingmaterial by the second polymer; and wherein the first and secondpolymers each comprise one or more polymers selected from the groupconsisting of biopolymers, inorganic polymers, organic polymers,conductive polymers, copolymers, fluoropolymers, polyterpenes, phenolicresins, polyanhydrides, polyketones, polyesters, polyimides,polyolefins, rubbers, silicones, silicone rubbers, superabsorbentpolymers, synthetic rubbers, vinyl polymers, and a combination thereof.19. The method of claim 6, wherein the binder material comprisescarboxymethyl cellulose (CMC).
 20. The method of claim 6, wherein thebinder material comprises a third polymer selected from the groupconsisting of PPBT, carboxymethyl cellulose (CMC), and styrenebutadiene.
 21. The method of claim 15 further comprising pressing thecomposite electrode to a predetermined density; wherein the dispersingcomprises ultrasonication; wherein the combining comprisesultrasonication; wherein the separating uses density separation; whereinthe filtering comprises vacuum filtering; and wherein the washing iswith at least one nonsolvent.